The present invention relates to marine vessels, more particularly to amphibious marine vessels that are suitable for performing auxiliary functions (e.g., transporting personnel and cargo between locations) in military operations or humanitarian relief operations.
For many years the United States Armed Forces have implemented various amphibious vessels for auxiliary purposes such as transporting cargo. For instance, a series of “LARC” (Lighter, Amphibious, Resupply, Craft) vessels has been used, commencing with the introduction in the late 1950's of the LARC 5, an aluminium-hulled wheeled amphibious cargo vehicle capable of transporting five tons. The LARC 5 is sufficiently mobile to traverse sand, coral beaches, unimproved roads, and off-road terrain, and to maneuver through a surf of 10-foot breakers. More recent LARC models have included the LARC 15 (which has a fifteen-ton payload capacity) and the LARC 60 (which has a sixty-ton payload capacity).
Generally speaking, the various LARC designs share the following characteristics: non-retractable wheels; low water speed; manned; rugged but high-maintenance. A LARC vessel includes wheels that are not retracted when the LARC vessel is in water; in fact, the LARC 60 has no suspension. LARC vehicles have traditionally been manned by at least a driver, usually assisted by a second crewman. LARCs generally are very rugged craft, exceeded their design service life, but are maintenance-intensive.
Most current marine systems for supplying fuel implement either a flexible fuel line or a fuel-carrying marine vehicle. A flexible fuel line extends from ship to shore. A fuel-carrying vehicle, such as a lighter, an LCAC, or a wheeled amphibious vehicle (e.g., LARC 5, 15, or 60), carries fuel trucks to the beach. When a flexible fuel line is used, it is necessary that the ship be fairly close to shore, and that the inland end of the pipe be close to the beach. Although a flexible fuel line arrangement affords a fuel capacity transfer rate that cannot be matched by any reasonable number of fuel-carrying vehicles, it is also vulnerable to enemy action because of its fixed and extensive nature. Fuel-supply systems involving parachutes have also been known, but parachutes drop very small quantities of fuel. All of the current fuel-supply systems are manpower-intensive, have limited at-sea range or sea-state capability, and require a separate fuel truck.
Because a pipe or hose such as a fuel line is such an easy target, the better fuel-supply approach in general is to deliver fuel in a mobile manner. Fuel is not the only liquid that requires transport, as bulk liquid distribution of fresh water to a water-scarce area is also of great import. A water-supply system should preserve water quality and taste. In addition, a fuel-supply system or water-supply system should reduce enemy risks to personnel, especially so as to minimize casualties due to enemy weaponry such as IEDs (improvised explosive devices). Accordingly, the need exists for a totally mobile system for supplying fuel and/or fresh water directly from a sea base to a secure forward area. The fuel/water supply system should be capable of at-sea transit from a sea base that is far offshore.
In general, a seagoing vessel is characterized by motion describable in terms of six degrees of freedom, viz., heave, surge, sway, roll, pitch, and yaw. The three kinds of translational ship motion are commonly referred to as heave (linear movement along a vertical axis), surge (linear movement along a horizontal fore-and-aft axis), and sway (linear movement along a horizontal port-and-starboard axis). The three kinds of rotational ship motion are commonly referred to as roll (rotational movement about a horizontal fore-and-aft axis), pitch (rotational movement about a horizontal port-and-starboard axis), and yaw (rotational movement about a vertical axis).
Use of radio frequency waves to remotely control devices such as vehicles has been known since the time of Nikola Tesla and his U.S. Pat. No. 613,809, issued 8 Nov. 1898, entitled “Method of and Apparatus for Controlling Mechanism of Moving Vessels or Vehicles,” incorporated herein by reference. The term “teleoperation,” in common usage, refers to human operation of a machine at a distance, is synonymous with the term “remote control,” and is frequently seen in robotic applications, for instance involving microsurgery or real-time control of remotely located mobile devices for exploration or mining.
Many vehicular land, sea, and air systems have demonstrated the efficacy of remote control of unmanned vehicles. Unmanned vehicles of interest include the USV (unmanned surface vehicle) and the RPV (remotely piloted vehicle). An example of RPV technology is the “Scan Eagle,” a UAV (unmanned aerial vehicle) that has a 3.2-meter wingspan, operates on JP5, and can stay aloft for a day. Use of the Scan Eagle has been demonstrated for launch and recovery via an integrated pneumatic launcher and a fifty-foot vertical recovery rope at sea, and as a fast unmanned riverine patrol boat providing a data link (including a bird's eye view) to the remote operator.